SIMULATION OF EDDY-CURRENT SIGNALS FROM MULTIPLE DEFECTS

The application of eddy current testing for structural integrity asses sment of heat exchangers is a well established practice. Service induc ed multiple defects in heat exchanger tubes produce difficult-to-evalu ate complicated impedance plane trajectories during periodic eddy curr ent examinations. Finite element simulations carried out to analyse in teractions in a two-defect system are discussed. Probable uncertainty in the interpretation of eddy current trajectories is highlighted. Sys tematic analysis of the results from these studies will simplify proce dures for on-line evaluation of eddy current signals. Copyright (C) 19 96 Elsevier Science Ltd.